Hi here is my situation. i just bought a 89 Trans am that had the 305tpi engine in it. The guy i bought it from put in a brand new 350 gm goodwrech engine in it Its a 350 tpi engine my problem is when im at full throttle in drive it shifts at only 3800rpms. Doesnt the 350 redline at 5500rpms? Shouldnt i be shifting at about about 5500rpms? The previous owner told me that near the throttile body by the manifold is a screw that can be adjusted so the tranny shifts at higher rpm. I have the 4 speed automatic that was reciently rebuilt. I have the a B@M shifter so i can shift to 1st gear and rap it up to higher rpms. 5000rpms seems to be pushing it though. I have the wimpy 6000rpm gauge in my car due to the 305 i suppose.What shouls i set the rpms at? Is that true about the screw that you can adjust?, or is that computer controlled Any info would be helpful thanks

 

It's not true about a screw you can adjust to change shift points (also not controlled by the computer). There is a cable attached to the trottle called the "throttle valve" cable, or TV cable, that goes down to the tranny and adjusts things in the tranny based on throttle position. However, this cable should only be adjusted as it was from the factory, as trying to vary the shift points by adjusting this cable will cause damage to the transmission.

1st check the adjustment of this cable (search on the tranny forum, you'll find it). Next, if it still doesn't shift correctly, there's something wrong with the govenor in the transmission. In either case, if the tranny was recently rebuilt, it should operate properly, so take it back to be adjusted properly.

Finally, the RPM limit for a stock TPI setup (whether 305 or 350) is about 5000 RPMs. Unless you have things like aftermarket shorter runners, any RPMs above that will not produce more power.

 

Hey thanks for the info i apprciate it!